Don't waste money on snake away...it's just mothballs.
My husband and I bought our home 3 years ago and have been battling with snakes since we moved in. Our attic was full of sheds, I had a 5 foot black snake in a spare room, a tiny one in the basement, a 4 footer at our wedding (it slithered under a neighbor's chair during the reception

)... and countless outside incidents...
Snakes are territorial, the one at our wedding was making a beeline for the chimney to go "back home" to our attic.
We're still sealing up our house and chimney. But the biggest improvement has been the yard, we've illiminated all brush, high weeds, and any debris laying around. We've moved our wood pile back 50 feet.
I once had a snake trying to get away from me, attempt to go into my garage, it slithered over a rope but veared away once it got close to the mothballs and went back into the yard.
Mothballs work, but are highly toxic. And you have to replace them everytime it rains. Put them in an old mik jug and poke holes in the bottom(so the smell comes out and they don't melt in the rain). Seal up everything and remove any hiding places.
Let me know what happens.
I HATE snakes...but they do cut back on rodents.